Method and apparatus for reducing chemical compounds.



E. WEINTRAUB.

METHOD AND APPARATUS FOR REDUCING CHEMICAL COMPOUNDS.

APPLIUATION FILED 001227, 1909.

1,046,03. v Patented De@.3,1912.

3 SHEETS-SHEET 1.

Condenser Y Inventor: Ezechiel Weintraub,

L. '/Mj?.

Hfs cqttovne;

E. WEINTRAUB. METHOD AND APPARATUS FDD RBDUGING CHEMICAL COMPOUNDS. APPLIOATION FILED 00T.27, 1909.

1906,@43., Patentd Dec. 3, 1912.

3 SHEETS-SHEET 2.

E. WEINTRAUB.

METHOD AND APPARATUS FOR RBDUCING CHEMICAL COMPOUNDS. APPLIGATION FILED 0032.27.190'9.

1,046,043, Patented Deo. 3, 1912.

3 SHEETS-SHEET 3.

i Ef? LL Inventor: t Ezechiel Weintraub,

Y TolZ/whom 'it-may concern:

V1L ATENT EZECHIEL WEINTBAUB, OF LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

v METHOD ANIDl .APPARATUS FOR BEDUCING CHEMICAL COMPOUNDS.

vSpecification of Letters Patent.

'Applicaties med october a?, isos. serial no. :mesa

Be it known that I, EZECHIEL WEINTRAUB,

Y a citizen of the United States, residing at Lynn, county of Essex, State of Massachusetts, lhave invented certain new and useful Improvements in Methods and Apparatus for Reducing Chemical Compounds, of

' which the following is a specification.

-My present invention relates to the art of reducing chemical compounds, Vand com rises amethod whereby an electrical arc 1s utilized to effect 'chemical change, and to remove the reduction products from the zone in which that change 1s belng carried out.

My invention also includes a novel form he practised.

Certain chemical compounds, as, for instance, chlorids and bromids, are to a certain extent reducible by hydrogenat high temperature, but the action is in many cases a reversible one, and hence the lyield oithe reaction may be very small. ccording to my present invention, the reverse react-ion is prevented by rapid removal of the reduction' product from the active zone.

My invention can beiused in general for the reduction of chlorids` and bromids which do not form solidsub-chlorids and subl bromide, as, for instance, zirconium chlorid and boron chlorid, and, lnsome cases, can also be used even when a sub-chlorid forms, as is the case with titanium chlorid. l will describe the operation as applied to Vboron chlorid; but it should be understood that 4 at about room temperature.

my invention is of a generic character, and can be applied to other materials. y V In the drawings forming part of this specification, Figure 1 is an-elevation, somewhat diagrammatic, of one form of apparatus for carryingout my invention; Fig. 2 is a -fragmental View of a modified form of apparatus for introducing theyreaction mixture into the arc; Fig. 3 is a detail View, being a cross section of one of the electrodes ot Fig. 42; Fig. 4 illustrates a modified 'form of apparatus for carrying out the invention; and Fig. 5 illustrates an apparatus adapted for the reduction of chlorids somewhat less volatile.y l

Boron chlorid is a colorless liquid, boiling It may be prepared by passing chlorin over crude boron and redistilllng the product over copper,4

such a l method can which is quicker and more effective than the usual shaking with mercury. is a reducing agent for the boron chlorid, I use pure, dry hydrogen, and as a'"-means for etecting the necessary temperature, l use an electrical arc, maintained between suitable electrodes. But in addition to this, the apparatus is so arrangedv that the arc blast drives the solid reduction product, namely, boron, out of the active zone and deposits it on the walls of the apparatus and on the electrodes. This .is t-he only solid product present, the three other substances, boron chlorid, 'hydrogen and hydrochloric acid, being all gaseous, are allowed to pass on to an absorbing or con densing chamber. This reaction differs from'any other reaction heretofore carried out in an electric arc in having the desired reaction product in solid form, all the other substances present being gaseous. This is especially favorable, both for the removal of the desired product, which is effected by the. arc blast itself, and forthe production of an absolutely pure product.

The functions of the are in removing the solid reduction product from the heated zone will be understood by appreciating that the emanations from the cathode spot move at high velocity and' start the solid reduction productions at high velocity. These velocities ;are,-no doubt, Very much higher than thatof the' slovi7 moving gas.

In the apparatus illustrated in l, the liquid boron chlorid 1is contained in a glass or copper Vessel 2, which is separated `from. the atmosphere by means of a small bulb 3 containing calcium chlorid for the absorption of moisture. The vessel 2 is surrounded by a refrigerating material,such as the ice bath 4 to prevent the vaporization of the boron chlorid. The boron chlorid is introduced` into the chamber 5 by means of a tube 6 having a stop cock 7 4The chamber 5 may be' heated if desired in any suitable manner, as by means of an electrical coil 8. A small quantity of the liquid chlorid is introduced at intervals into the chamber 5, where it is vaporized and the vapor carried away with a stream of hydrogen entering by the tube 9. The mixture of hydrogen and boron chlorid va or leaving the chamber 5 through an exit tu e l0 passes into the two'branch tubes 11 and 12, which carry the mixture into the main arc chamber 13. This chamber is made Vof glass or copper, or other suitable material,

Patented nee. e., 191e.

and is provided with an inlet tube 14g for a supply of hydrogen, and with an outlet tube 15, through which the unused h drogen and boron chlorid, as well as the ydrochloric acid forming as' a by-product of the reaction, are led to other parts ofthe apparatus. V'Vithin the arc chamber 13-,pro'ect the electrodes 16, 17, each consisting o copper tub.

ing doubled on itself and cooledinternally b a stream of water. For the sake of simp icity, the water supply pipes have been merely indicated in the drawing. Only one pair of electrodes is shown in the drawing, thou h more can be used ina single arc cham er il desired. An alternating Icurrent,- arc is preferably used, the current being supplied as indicated from a transformer 18, the primary of which is in circuit with suitable reac'tance coils 19, 20. The mixture of hydrogen and boron chlorid is introduced directly into the hot zone of the arc by means or" the nozzles 21,y 22 of refractory material such as silica. The reduction of the chlorid by hydrogen is effected yaccording toA the following treatment:

Bo18+3H=3Ho1+B- The are blast throws the solid particles of the reduced boron out of the hot zone against the walls of the arc chambers and against the electrodes themselves, and the hydrochloric acid gas is carried along with the hydrogen and any reduced boron chlorid toward the upper part' of the arc'chamber, where it is yremoved by the tube 15. 'I he boron deosited on the electrodes themselves is fused y the heat of the are, so that apart of the boron is yielded directly as a homogeneous fused product. The arc then runs between two boron electrodes, the boron in some cases dropping oil after having grown to a certain size, and another fused deposit of boron forming on the electrode. In this connection, the choice of the electrode material is of great importance. It must have 'no aiiinity whatever for the reductlon'product,

so as not to combine with the productdepo-siting and melting on it; and, secondly, it must not electrically disintegrate and mix with tlfe powdered product. I have found that in the case of boron, copper `fulfils these conditions perfectly; silver and gold also act satisfactorily. If a second arc 1s. arranged lilre the first and in series with 1t, 1t will act on any reduced boron chlorld passing the iirst arc. The mixture of gases coming from the main arc chamber 13, and consisting of hydrogen, hydrochloric acid gas and unreduced boron'chlorid pass to a condenser 23, in which the boron chlorid not acted upon, is again condensed to the l1qu1d form, and yis caught in a suitable vessel 24. The condenser is of the usual form, and a discussion of the same in thi's connection is unnecessary. The mixture of hydrogen and .'iedhydrogen passes out by of boric anhydrid scribed the product as a brownish practically non-conductive for electricity,

Prior to denser by means of containing sodium gam, or other substance Asuit-a le for'combinlng with the hydrochloric acid. The puri- Inay be used over Fig. 2 showsamodiied form of apparatus upon is introduced by means of tubes 28, 29 passing centrally 4through the electrodes. The electrodes proper consist of copper and are water-cooled, similar to the electrodes ldescribed in connection with providing the electrodes with a central par tition extending nearly to the end thereof, and shownbest in sectionl as 30 in -Fi .y 3. ,The cooling Huid passes inron one side o? the partition and out on the other side.

The boron produced as vabovedescribed is not the material commonly designated` as boron, in the technical literature. Moissan made what he called boron by reduction with magnesium. He deand vaporizable without fusion. my own investigation of boron and its compounds, this was the material generallyirecognized among chemists as boron. I have, yhowever, demonstrated that it is not pure boron at all. If-the-reaction is carried4 out as described by investigators preceding Moissan, the product is magnesium borid, containing more or less magnesium; if. the reaction 1s carried out according to Moissan, using an excess of boric anhydrid, a boron sub-oxid is formed mixed with more or less magnesium borid. I have found that can be fused into dense bodies having aconchoidal fracture, and a hardness considerably greater than sapphire. Its melting point is about 20009 C. andis not far from 2300 C Its vapor tension is high. While it has a high resistance whenlcold,l itpossesses a negative temperature coeiicient of that it acts as a fair conductor of electricity the heating action of the current. In an application,

May 28, 1912 as' a division of the present application, claims are made on'boron as an article ofv manufacture. 997,879, I have described and claimed the vacuum the impure boron compound obtainmagnesium. In Patent No. 1,019,392, -I

of boron by'thermal treatment of themagnesium reduction product by a high voltage arc operating in hydrogen. "In Patent No.

Fig. 1,'thecir- 'V Aculation of cooling Huid being obtained by powder,

able when boric anhydrid is reduced withl hydrochloric acid gas passes from the con-A I a tube 25 to a chamber 26 hydroxid'o sodium amall a tubel 27, and Y in which tie mixture of gases to be acted pure boron 1s black,` not brown, and that it resistance of` unprecedented'-magnitude, so

by the natural rise in conductivity due to Serial No.700,151 led In my Patent No.

method of makingl boron 'byheating in aj i have described and claimed the preparation 1,019,569, I vhave described and claimed the method of making boron from a mixture of boric halid and hydrogen in contact with a heated surface.

It should be understood that the basic.

In Fig. 4 a modified form of apparatus is illustrated, in whichV a stream'of hydrogen is passed by means of tube 3l over the surface of the liquid boron chlorid 32, which is contained ina-vessel surrounded by ice, or other cooling means 33, so as to control its p evaporation. The hydrogen carrying with it boron chlorid vapor is passedl into a main arc chamber, which is similar to that described in connection with Fig. 1; but in this case the reaction mixture is introduced at the bottom of the chamber, from where it is passed upward through a plurality of arcs 4 formed between water-cooled copper electrodes. Two sets of electrodes, 34, and 36, 37, have been shown; buta greater numlber can be used. The electrodes are connected in series to the secondary of the high voltage transformer, in the same manner as described in connection with Fig. 1. The reduction of the' boron takes place in the same manner, and the description need not be repeated at this point. The unused hydrogen and boron chlorid, and the by-produetlconsisting of hydrochloric acid,pass out of the arc chamber through a tube 38 into an absorption vessel 39 containing sodium hydroxid or sodium amalgam, which combine with the hydrochloric acid. rllhe mixture of boron chlorid and hydrogen, from which ythe hydrochloric acid has now been removed, pass on by means ofthe tube 40 to a second arc chamber 4l containing electrodes 42, 43, which likewise consist of copper, and are water-cooled. In this chamber a further reduction of boron chlo-rid takes place. If desired, the unused hydrogen escaping through outlet tube 44 can be purified in the manner described in connection with Fig. 1, and used over again.

In Fig. 5 is illustrated an apparatus arrangedv particularly for the 'reduction of compounds requiring the application of externalheat to bring them to a vaporized state. The apparatus is provided with a heating chamber 45, in which a chlorid, such as zirconium chlorid in granular form is placed. The chamber is heated by gas flames from burners 46, or in any other suitable manner, and is provided with an inlet tube 47, through which hydrogen or other reducing gas is admitted for mixing with the vaporized chlorid. The mixture of gases passing out of chamber45 enters the arc chamber 48, and is there subjected to the action of an alternating current are maintained between the water-cooled copper lelectrodes 49, 50. As in the cases heretofore described, the arc blast imparts to the solid reduction product such rapid movement that the particles are quickly removed from the hot zone and are deposited on the walls of the arc chamber, or o-n the electrodes themselves. Beyond arc chamber 48 there is provided a condenser 51, water-cooled, if desired; but air-cooling will suffice in this case.

In this chamber collects any unreduced chlorid. The mixture of hydrogen and hydrochloric acid escaping .from this condenser through tube 52 can be puriiied by passing throughan absorbing apparatus 53, contaming sodium hydroxid or other suitable material. The hydrogen leaving the absorbing chamber by way of outlet tube 54 can be sebsequentlyused over again in the cycle of reduction.

v"What I claim as new and desire to secure by Letters Patent of the United States, is,

1. The method of eiecting in a gaseous mixture a chemical reaction normally reversible, which consists in feeding said mixture to an arc capable of supplying the necessary heat and arranged to drive from its heated zone any solid reduction product,

.thereby preventlng the reverse reaction by rapid removal from the active zone of any solid reduction product which might otherwise be attacked.

2. The method of reducing a '-.faporized halid with hydrogen, which consists in passing a mixture of said materials directly through an arc.

3. The method of reducing a vaporized halid with hydrogen, which consists in feeding a mixture thereof to an arc capable of driving from its heated zone any solid reduction product.

4. The process of producing boron which consists 'in acting upon boron halid with hydrogen at high temperature.

5. The method which consists in subjecting a mixture ofboron halid and reducing agent to a temperature suiiiciently high to initiate a reaction in said mixture, and removing one of the products of the reaction from the reaction zone, with suiiicient rapidity to prevent in large part the reverse reaction.

6.` The method of producing boron, which consists in passing a mixture of boron chlorid and hydrogen into an arc capable of effecting chemical union between the hydrogen and the chlorin with liberation of' pure boron.

7. The method of making pure boron, whichconsists in passing a mixture of vaporized boron halid and hydrogen into an alternating current arc maintained between cooled electrodes consisting of material inert with respect to boron.

i communicating Withy said Vaporizin'g cham'-4 i chemical compounds, 'thefcombinat-ionof a vaporizing chann-ber; a' hydrogen inlet. forr 8. The methodof producing' pure'bor'on,

which consists in'pa'ssi-n 'amixture of boron ch'lorid and hydrogenrinto an alternating current are maintainedbetween cooledcopperjelectrodes. .J

9." The method -WhichconsistsI inpassmg Waterf Va mixture of hydrogen and a reduciblelchlorid into an' arc to 'effect reduction. f the chlorid, absorbing. the hydrochloric acid vresul'ting. from the* reaction', and ultimately returning the regenerated hydrogen `for use in the reduction of more'zchlorid.

'10. 'In an apparatus fory the reductionfo chemical compounds, a vaporizing chamber, means for mixing a reducing.A gas with mas terial there vapori'zed, ,and an lare chamber ber, ,end provi'ded with Iiifea'ns for-.maintaining` anarc between electrodes chemically inf4 active.. y' t 11. In an apparatus for the .reduction of saidcharnber, an arech'amber communicat- '"1 ing with sa'idy'aporizing chamber, and a means for maintainingzan alternatmgcurl 'rent arc Withinsaid larc chamber between electrodes chemically inactive with respect.

to the materials under treatment.

'12. In a reduction apparatus, the combi nation of a gas tight chamber, lmeans -for supplying theretoa vaporized chlorid and a. reducingas, and means 'for maintaining in said chamber. an are 'capable' of ettectingV chemical reaction between vsaid Vapor and l ...11,2 l noaa-,043i

'said f gas with simultaneous deposition on the walls of said chamber of any solid productl resulting vfrom said reaction.

13. In 'an apparatus for 'eiecting chemicalreactions ,normally reversible Wlth production ofga solid product, the combination of a closed arc chamber, means for supplying thereto the reaction mixture, and means Within said chamber for effecting the ldesired reaction with .quick removal from the active zone of atleast one solid product of' said reaction.

1 14. In an apparatus for the reduction of chemicalcompounds, a vaporizing chamber,

an are chamber`,;means .for supplying a reducing gas to. the -nvaporizing chamber to transport vaporized material into said arc chamber,gmeans lfor mixing additional yreducing gas with said vaporized material, meanafor vmaint-nining an arc into Which said mixture is fed, and an absorbing cham- "berfinto 'which some of the by products are conducted.' y .y -`l5. 1n -anarc furnace for producing boron, v arcing electrodes consisting of a metal of the copper- -group .fandfmeans for supplyingI to-sa'id'electrodesaj gaseous mixture contain` ing a boron y halid.

In Witness whereof, have hereunto set hand this 26th day of October, l1909. EZECHIEL -WE1NTRAUB- ,VVitness'es: l I

JoHNA.- MCMANUS, Jr.,

'p (liframnis-v A.' BARNARD.- 

